Project
Nine Eagles Sky Runner brushless and Futaba conversation with NANO FPV
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Published
Apr 23 2012 by FaTe
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you look back through previous projects here on Nine Eagle products you'll see these models are very versatile and you can modify them like crazy. I like them best because of their size, this Sky Runner is 20CM bigger than the Xtra 300 with a 70CM wingspan making for a great NANO FPV platform.

Nine Eagles product page for Sky Runner - click here to visit


2.4GHz 3CH | MODEL NO.:RX:NE R/C 772B | TX:NE-024G

Wing span:27.7"(703mm)

Overall length:20.2"(514mm)

Height:6.14"(156mm)

Flying weight:3oz.(85g)

Power system:N60 motor

Battery: 7.4V 250mAh Li-Po
/media/Sky-Runner/original-sky-surfer
This is the stock Nine Eagles Sky Runner and being honest its a very nice looking model. However it does come with a standard N20 brushed motor with a 250mAh 2 cell lipo which should give you about 10 minutes flight time on average.
/media/Sky-Runner/stock-electronics
Here you can see the standard RX/ESC/linear servo board and its all fairly tidy looking. I'm not interested in these electronics though and so I took them out having never used them. (including motor)
/media/Sky-Runner/empty-fuselage
Once empty you can see there's quite a bit of room (when talking about micro electronics).
/media/Sky-Runner/new-servos-installed
Here I've fitted 2 * 3.2 gram micro servos not linear like standard. Why? More torque, more throw (travel distance) and more reliable.
/media/Sky-Runner/4-channel-receiver-installed
I took the RfSky 4 channel receiver out of it's casing and used heat shrink pipe to seal it, this still fits in front of the servos on the bottom of the fuselage nicely.
/media/Sky-Runner/lipo-size-differance
On the left is the stock 250mAh 2C lipo, on the right is the new 2C lipo 500mAh (it also fits up to 650mAh packs no problem).
/media/Sky-Runner/lipo-fits-stock-placement
There is no need to modify the fuselage to fit the bigger lipo, it fits where the stock goes without doing a thing - pretty nifty Nine Eagles :)
/media/Sky-Runner/plywood-out-runner-motor-mount
Now the stock inrunner brushed motor is not so good or powerful. Most brushless inrunners this size still don't have the power I want so I made an outrunner motor mount using 2MM plywood first UHU por glued in place to hold it while I used foam safe CA glue around the edges for a final bond.
/media/Sky-Runner/turnigy-motor-and-esc
Now I can fit my 1450kv Turnigy brushless motor, it's running on a 12A Turnigy Plush ESC.
/media/Sky-Runner/electronics-fitted
The ESC sits in front of the motor mount for best air flow cooling wise. Now all electronics are fitted.
/media/Sky-Runner/fuselage-slot-cut-fit-bigger-propeller
The standard propeller is TINY and would allow for maybe winds upto 10-15MPH, beyond that and you'd fly backwards if at all. So I cut a slot out of the fuselage and used tissue paper to create a cover by apply CA glue to harden it in place. That's a 6*4 prop :)
/media/Sky-Runner/carbon-fiber-boom-support
Of course some structural integrity was lost cutting out for the propeller, so I added a 3MM carbon fiber rod down the bottom of the fuselage between the foam. I used CA glue to fix it in place. The tail boom is again solid.
/media/Sky-Runner/137-grams-flying-weight
Here you can see the all up weight (AUW - including battery) is 137 grams, this motor can push another 100 grams on top of that so perfect.
/media/Sky-Runner/easystar-sky-runner-comparison
A comparison against a Multiplex Easystar , Nine Eagles did you use tracing paper??????
/media/Sky-Runner/setting-up-at-field
Setting up at the field only 18 hours after buying the model, never using stock electronics to being at club ready for maiden flight all converted.

While this conversation was not as simple as others simply because of the fuselage inner design. Overall though this model 100% rocks, an amazing platform for micro/nano/sub-nano FPV flying.
The maiden flight, remember this model is 3 channel with no ailerons (yet lol). It was 16-22MPH winds so the plane kinda gets taken away until I got a feel for the plane, so the first 1 minute is a bit out there. This is also my first video with a slide show of the build in it, thought I'd try something new.

This model flies like a dream, not only is the COG (Center Of Gravity perfect - 13MM into the wing with this set-up) perfect but when I just glide with no power and let go of sticks it casually creeps forward into the wind (again 16MPH+!). It did this better with the 610mAh Rhino 2C lipo being 9 grams heavier it likes a bit of nose heavy.

I ran some power tests with the 500mAh:

  1. After 5 minutes first maiden flight (video was edited) I had 69% left.

  2. A further 10 minute flight left the lipo at a nice 25% which is where I like to stop.


So after really using lots of throttle to get idea on speed and fighting wind gusts I was able to fly 15 minutes easily. A calmer day and more gliding I could easily get another 10+ minutes.

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